diff --git a/tiled/catalog/migrations/versions/e05e918092c3_add_closure_table.py b/tiled/catalog/migrations/versions/e05e918092c3_add_closure_table.py
index 590bac40f..071a7b066 100644
--- a/tiled/catalog/migrations/versions/e05e918092c3_add_closure_table.py
+++ b/tiled/catalog/migrations/versions/e05e918092c3_add_closure_table.py
@@ -148,6 +148,17 @@ def upgrade():
     )
     logger.info("Inserted root node with id=0.")
 
+    # 4. Insert self-referential records into nodes_closure for each node, including the "root" node
+    connection.execute(
+        sa.text(
+            """
+        INSERT INTO nodes_closure(ancestor, descendant, depth)
+        SELECT id, id, 0 FROM nodes;
+        """
+        )
+    )
+    logger.info("Inserted self-referential records into 'nodes_closure' for each node.")
+
     # 5. Populate the 'parent' column of the 'nodes' table based on the 'ancestors' column
     json_len_func = (
         "jsonb_array_length"
@@ -196,6 +207,7 @@ def upgrade():
             WHERE {json_len_func}(child.ancestors) >= {depth + 1}
             AND {condition_statement}
             AND parent.parent = child.parent
+            AND child.id != parent.id;
         """
             )
         )
@@ -217,24 +229,6 @@ def upgrade():
         )
     logger.info("Completed updating 'parent' column recursively.")
 
-    # 7½. Insert self-referential records into nodes_closure for each node, including the "root" node
-    #     (Any conflicts here are clearly a mistake, so we just clobber them)
-    conflict_strategy = (
-        "ON CONFLICT (ancestor, descendant) DO UPDATE SET depth = EXCLUDED.depth"
-        if connection.engine.dialect.name == "postgresql"
-        else ""
-    )
-    connection.execute(
-        sa.text(
-            f"""
-        INSERT INTO nodes_closure(ancestor, descendant, depth)
-        SELECT id, id, 0 FROM nodes
-        {conflict_strategy};
-        """
-        )
-    )
-    logger.info("Inserted self-referential records into 'nodes_closure' for each node.")
-
     # 8. Update index in the 'nodes' table: drop old, add new
     op.drop_index("top_level_metadata", table_name="nodes")
     op.create_index(